(1) Field of the Invention
The present invention generally relates to electrical grounding equipment and more particularly to a shield ground adapter (SGA) designed to shunt high level electromagnetic (EM) energy from cable shields to a metallic boundary such as a kickpipe/stuffing tube (KP/ST) assembly, through which the cable passes. The EM energy can be caused by lightning or high level EM electromagnetic sources including the energy from an electromagnetic pulse (EMP). This shunting of EM energy from the cable shield to the metallic boundary, through which the cable passes, prevents the high level currents and voltages, with resulting EM fields, from penetrating into the space protected by the metallic boundary.
(2) Description of the Prior Art
Prior to the present invention all shield ground adapters utilized either soldered or spring type shield ground adapter devices that are located outside of the kickpipe/stuffing tube assembly. These devices were then screwed into the kickpipe/stuffing tube assemblies to obtain their required connections to the ground plane or metallic boundary.
With all of these devices, performance depends on the quality of the shield ground adapter to kickpipe/stuffing tube thread connection. It has been demonstrated that shield ground adapter performance, both in the laboratory and onboard a Naval ship, has been shown to degrade in performance (versus frequency and time) by over 120 dB. This makes the EM performance of existing shield ground adapters almost non-existent only weeks after being screwed into the kickpipe/stuffing tube assembly.
As previously stated, all prior art shield ground adapter devices, known by applicant, are presently connected outside the kickpipe/stuffing tube assembly and require special mechanical assemblies to house the cable-to-shield ground adapter connection, and then the entire assembly must be environmentally sealed to prevent long term degradation of the shield ground adapter EM performance.